Connection unit, a board for mounting a device under test, a probe card and a device interfacing part

ABSTRACT

A connection unit for electrically connecting a DUT mounting board, on which an IC socket is mounted, with a testing apparatus for testing an electronic device inserted into the IC socket, the connection unit has a holding substrate provided to face the DUT mounting board and a connection-unit-side connector, which is provided on the holding substrate to be able to change a position of the connection-unit-side connector on the holding substrate, for being connected to a performance-board-side connector included in the DUT mounting board.

The present application is a continuation application of U.S.application Ser. No. 11/487,091 filed Jul. 14, 2006 now U.S. Pat. No.7,518,379 which is a continuation of U.S. application Ser. No.10/800,189 filed on Mar. 12, 2004 now U.S. Pat. No. 7,098,680 which is acontinuation of PCT/JP03/13595 filed on Oct. 24, 2003, which claimspriority from Japanese Patent Applications Nos. 2002-317287 filed onOct. 31, 2002 and 2002-338560 filed on Nov. 21, 2002, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a testing apparatus. More particularly,the present invention relates to structures of a board, generally calleda performance board, a probe card or a socket board for mounting adevice under test (“DUT”) and a connection unit for connecting the DUTmounting board and the body of the testing apparatus.

2. Description of the Related Art

FIG. 14 shows a schematic structure of a conventional IC testingapparatus, which is described first hereinafter.

In large, the IC testing apparatus includes a main frame 1, a test head2 and a DUT interface part 3. The main frame and the test head 2 areconnected by a cable 4, and the DUT interface part 3 is mounted on andconnected to the test head 2.

In this example, the DUT interface part 3 includes, for example, asubstrate 11, a motherboard 10 provided with a plurality (e.g.thousands) of cables 12 (“a motherboard unit”), a DUT mounting board 20generally called a performance board, and an IC socket 320. Thesubstrate 11 is provided with a connector (not shown) for connecting tothe test head 2 on its lower surface.

The lower end of the cable 12 is soldered on or connected via theconnector to the substrate 11, and the upper end of the cable 12 isconnected to the DUT mounting board 20 via a connector (not shown), etc.In this example, one IC socket 320 is mounted on the DUT mounting board20. As shown in FIG. 14, there is shown DUT (IC under test) 40 mountedon the IC socket 320. Further, there is also shown a cover 13 whichcovers the cable 12.

FIG. 15 shows a conventional structure of DUT mounting board 20according to the above structured IC testing apparatus and a schematicconnection relationship between the DUT 40 and a connector 15 (on theupper end of the cable 12) in regard to the DUT mounting board 20, wherethe IC socket 320 is omitted.

The DUT mounting board 20 has a structure of a multilayer printedcircuit board, on the upper surface and the lower surface of whichelectrode pads 21 and 22 are formed for connecting to the DUT 40 and theconnector 15, respectively.

Through holes 23 are formed on the corresponding electrode pads 21 and22 on the upper and lower surfaces of the board 20. The through holes 23are connected with internal layer wiring patterns 24. In other words,the conventional DUT mounting board has a structure of a multilayerprinted circuit board using through holes 23 for connecting theelectrode pads 21 and 22 with the internal layer wiring patterns 24.See, for example, in an article of “Build-Up Multilayer Printed WiringBoard Technology”, Page 7 to 8, written by Kiyoshi Takagi, published byNikkan-Kogyo Newspaper, Inc., Jun. 20, 2000. Arrows in FIG. 14 showflows of electrical signals.

However, recently, high speed testing is required for the IC testingapparatus, and high speed, e.g. 4 Gbps, signals are used for the highspeed testing of the DUT.

As the signal speed becomes faster, design of surroundings of thethrough holes 23 of the conventional DUT mounting board 20 of the abovedescribed structure shown in FIG. 15 affects reflections and bandblockings.

In other words, as designated by dashed line in FIG. 15, since a stubpart 25 (hereinafter, parts unnecessary for transmission lines arecalled stub parts) for the through hole 23 is large (or long),capacitance of this stub part 25 becomes a problem of producing waveformdistortion and capacitive reflection, which cause deterioration ofsignal quality (or waveform quality). Therefore, the conventional DUTmounting board 20 has a problem of not coping with high speed signals.

In order to overcome the above problem, it is an object of the presentinvention to provide a DUT mounting board which can cope with high speedsignals with reduced capacitance of stubs, and a device interface partof an IC testing apparatus including a DUT mounting board solving theproblem.

Further, in case of conventional testing of electronic devices likesemiconductor devices, there have been used a testing apparatus forgenerating test signals, a performance board for mounting an electronicdevice and a connection unit for electrically connecting the testingapparatus with the performance board. The performance board and theconnection unit respectively have connectors engaging each other. Theconnector of the connection unit receives test signals from the testingapparatus and provides them to the electronic device via the connectorof the performance board.

The connectors of the connection unit and the performance board arerespectively fixed on predetermined locations of the connection unit andthe performance board, and electrically connect the testing apparatuswith the performance board by engaging corresponding connectors asdisclosed, for example in Japanese Patent Application Laid-Open No.2000-81461. For example, respective connectors are provided onneighborhoods of the outermost circumferences of the connection unit andthe performance board.

However, since the connector of the connection unit is fixed, it isdifficult to connect the connection unit with the performance boardwhere the location of the connector is different. Thus, it is requiredto prepare each connection unit which has each connector arrangementcorresponding to each performance board of different connector location.

For example, in case a high frequency signal is applied to theelectronic device, it is required to arrange the connector of theperformance board to be near the electronic device in order to shortenthe length of the transmission line from the connector of theperformance board to the electronic device. In this case, it is alsorequired to arrange the connector of the connection unit on a locationcorresponding to the location of the connector of the performance board.But, since the connector of the conventional connection unit is fixed,it is required to prepare a connection unit for high frequency signals.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide aconnection unit, a DUT mounting board, a probe card and a deviceinterface part, which are capable of overcoming the above drawbacksaccompanied by the conventional art. The above and other objects can beachieved by combinations described in the independent claims. Thedependent claims define further advantageous and exemplary combinationsof the present invention.

According to the first aspect of the present invention, a connectionunit for electrically connecting a DUT mounting board, on which an ICsocket is mounted, with a testing apparatus for testing an electronicdevice inserted into the IC socket, the connection unit comprises aholding substrate provided to face the DUT mounting board and aconnection-unit-side connector, which is provided on the holdingsubstrate to be able to change a position of the connection-unit-sideconnector on the holding substrate, for being connected to aperformance-board-side connector which the DUT mounting board comprises.

The holding substrate may comprise, in case a position of theperformance-board-side connector varies according to kinds of the DUTmounting board, a means for moving the connection-unit-side connector toa position corresponding to the varied position of theperformance-board-side connector.

The connection-unit-side connector may be detachable from the holdingsubstrate, so that the connection-unit-side connector detached from theholding substrate may be re-attached to other holding substrate on whicha performance-board-side connector is provided in a different position.

The connection-unit-side connectors may be plural, and distances betweenthe plurality of connection-unit-side connectors can be changed on theholding substrate.

The connection-unit-side connector may be provided in order that thedistance can be changed, with regard to the position of the IC socketwhere the connection unit and the DUT mounting board are connected.

The connection unit may further comprise a connection cable, of which anend is fixed to the connection-unit-side connector, for electricallyconnecting the connection-unit-side connector and the testing apparatus,wherein the holding substrate has a penetrating hole, of which adiameter admits the connection-unit-side connector, at a position tohold the connection-unit-side connector.

The connection unit may further comprise a connection cable, of which anend is fixed to the connection-unit-side connector, for electricallyconnecting the connection-unit-side connector and the testing apparatus,wherein the holding substrate has a penetrating hole, through which theconnection cable passes, between a plurality of positions to be able tochange the connection-unit-side connector.

The holding substrate holds the connection-unit-side connector to beable to change the position in either a radial direction or an axialdirection, taking a position of the IC socket, where the connection unitand the DUT mounting board are connected, as a center.

The cross sections of the IC socket and the connection-unit-sideconnector may be rectangular respectively at a surface substantiallyparallel to the holding substrate, and the holding substrate may holdthe connection-unit-side connector so that a longer side of the crosssection of the connection-unit-side connector faces a nearest side ofthe cross section of the IC socket, in case the connection-unit-sideconnector is positioned most closely to the IC socket, with regard to adirection of diameter.

The holding substrate may comprise a plurality of connector positioningmembers, respectively provided at predetermined positions on the holdingsubstrate, for designating positions where the connection-unit-sideconnector may be changed.

The connection-unit-side connector may comprise either groove orprotrusion, one of which is inserted into one another, each of theplurality of connector positioning members comprises corresponding oneof groove or protrusion, and the holding substrate may hold theconnection-unit-side connector by engaging the groove or protrusion ofthe connection-unit-side connector with the groove or protrusion of theconnector positioning member.

A plurality of IC sockets may be placed on the DUT mounting board, andthe connection unit comprises a plurality of connection-unit-sideconnectors corresponding to the plurality of the IC sockets, whereby theholding substrate holds each of the plurality of connection-unit-sideconnectors so that a position of the connection-unit-side connector maybe changed.

The connection unit further comprise a small diameter performance boardpositioning member, provided on the holding substrate, for designating aDUT mounting board of which a diameter is smaller than a predetermineddiameter, and a large diameter performance board positioning member,provided at a position farther from the IC socket than a position of thesmall diameter performance board positioning member on the holdingsubstrate, for designating a DUT mounting board of which a diameter islarger than a predetermined diameter.

According to the second aspect of the present invention, a DUT mountingboard for electrically connecting an electronic device and a testingapparatus for testing the electronic device, the DUT mounting boardcomprises an IC socket for holding the electronic device, a socketsubstrate for holding the IC socket, a high-frequency signal connectorfor supplying a test signal from the testing apparatus to the IC socket,and a low-frequency signal connector, provided farther from the ICsocket than a position of the high-frequency signal connector, forsupplying a test signal of which a frequency is lower than the testsignal which the high-frequency signal connector provides from thetesting apparatus to the IC socket.

The socket substrate may comprise a single-sided hole for high-frequencywhich is electrically connected to the high-frequency signal connectorand extends from a bottom surface, where the high-frequency signalconnector is provided on the socket substrate, to an intermediate layernot reaching a top surface of the socket substrate, and a through holefor low-frequency which is electrically connected to the low-frequencysignal connector, is provided at a peripheral portion of the socketsubstrate with regard to the single-sided hole for high-frequency, andextends penetratingly from a bottom surface, where the low-frequencysignal connector is provided on the socket substrate, to a top surfaceon which the electronic devices are placed.

The socket substrate may further comprise a through hole forhigh-frequency which is electrically connected to a high-frequencyterminal pin of the electronic device and extends penetratingly from thetop surface to the bottom surface of the socket substrate, and ansingle-sided hole for low-frequency which is electrically connected to alow-frequency terminal pin of the electronic device, is provided at aperipheral portion of the socket substrate with regard to the throughhole for high-frequency, and extends from the top surface to anintermediate layer not reaching the bottom surface of the socketsubstrate.

The socket substrate may be a multilayer board in which a plurality ofwiring layers is formed, wherein the socket substrate further comprisesa low-frequency signal wiring, formed on one of the layers, forelectrically connecting the through hole for low-frequency with thesingle-sided hole for low-frequency, and a high-frequency signal wiring,formed on a layer lower than the layer on which the low-frequency signalwiring is formed, for electrically connecting the single-sided hole forhigh-frequency with the through hole for high-frequency.

According to third aspect of the present invention, a DUT mounting boardfor electrically connecting an electronic device and a testing apparatusfor testing the electronic device, the DUT mounting board comprises asocket substrate having a plurality of layers on which wirings areformed respectively, and a connector, provided on a bottom surface ofthe socket substrate, for supplying a test signal from the testingapparatus to the electronic device, wherein the socket substratecomprises a signal wiring, formed on a layer of the socket substrate,for transferring the testing signal to the electronic device, aplurality of upper layer ground (GND) wirings, formed on an upper layerthan the signal wiring, for being connected to a ground potential, aplurality of lower layer GND wiring, formed on a lower layer than thesignal wiring, for being connected to the ground potential, and ansingle-sided hole, extending from a bottom surface to a top surface ofthe socket substrate, for electrically connecting the connector and thesignal wiring, whereby a horizontal distance between at least one of theupper layer GND wiring and the single-sided hole is greater than ahorizontal distance between at least one of the lower layer GND wiringand the single-sided hole.

A horizontal distance between a first one of the upper layer GND wiringsclosest to the signal wiring and the single-sided hole may besubstantially the same as a horizontal distance between the lower layerGND wiring and the single-sided hole, and is smaller than a horizontaldistance between a second one of the upper layer GND wirings and thesingle-sided hole.

The single-sided hole may extend from a bottom surface of the socketsubstrate to an intermediate layer not reaching a top surface of thesocket substrate.

According fourth aspect of the present invention, a DUT mounting boardfor electrically connecting an electronic device and a testing apparatusfor testing the electronic device, the DUT mounting board comprises asocket substrate having a plurality of layers on which wirings areformed respectively, and a connector, provided on a bottom surface ofthe socket substrate, for supplying a test signal form the testingapparatus to the electronic device, wherein the socket substratecomprises a signal wiring, formed on a layer of the socket substrate,for transferring the testing signal to the electronic device, ansingle-sided hole, extending from a bottom surface of the socketsubstrate to an intermediate layer not reaching a top surface of thesocket substrate, for electrically connecting the connector and thesignal wiring, and a plurality of GND wirings for being connected to aground potential, which are formed at one of the layers excluding thesignal wiring except a place where the single-sided hole is formed, incase the single-sided hole extends to the top surface of the socketsubstrate.

According fifth aspect of the present invention, a probe card forelectrically connecting an electronic device with a testing apparatusfor testing the electronic device, the probe card comprises a probe pinfor being electrically connected to a terminal of the electronic device,a probe board for holding the probe pin, a high-frequency signalconnector for supplying a test signal from the testing apparatus to theprobe pin, and a low-frequency signal connector, provided farther fromthe probe pin than a position of the high-frequency signal connector,for supplying a test signal, of which a frequency is lower than the testsignal supplied to the probe pin by the high-frequency signal connector.

According sixth aspect of the present invention, a DUT mounting boardfor interfacing a test signal used for testing DUT in an IC testingapparatus, comprises a multilayer printed circuit board, in which afirst one of both ends of an internal layer wiring pattern is connectedto a through hole, and a second one of the both ends of the internallayer wiring pattern is connected to an SVH (Surface Buried Via Hole),and upper and lower ground layers, between which the internal layerwiring pattern is interposed, wherein the ground layers are distancedfrom a stub part of the SVH in order to reduce deterioration of transferproperties according to the stub part, whereby the SVH, internal layerwiring pattern and through hole form wiring connection between top andbottom surfaces of the printed circuit board.

The DUT mounting board may comprise a plural layer printed circuit boardcomprising an internal layer wiring pattern and a ground layer, whereinat least two the plural layer printed circuit boards are bonded, andthrough holes, connected to one of the internal layer wiring patterns,are formed to produce a multilayer printed circuit board, and the SVH,which connects an end of the internal layer wiring pattern, is formedout of the through holes, so that predetermined characteristic impedanceis formed according to the width of the internal layer wiring patternand the distance between the upper and the lower ground layers.

According seventh aspect of the present invention, a device interfacingpart of IC testing apparatus for interfacing electrical signals flowingbetween a test head and a DUT, comprising a DUT mounting board forinterfacing electrical signals used for testing DUT, the DUT mountingboard comprises a multilayer printed circuit board, in which a first oneof both ends of an internal layer wiring pattern is connected to athrough hole, and a second one of the both ends of the internal layerwiring pattern is connected to an SVH, and upper and lower groundlayers, between which the internal layer wiring pattern is interposed,and wherein the ground layers are distanced from a stub part of the SVH(Surface Buried Via Hole) in order to reduce deterioration of thetransmission characteristic according to the stub part, whereby the SVH,internal layer wiring pattern, and through hole form wiring connectionbetween top and bottom surfaces of the printed circuit board.

The summary of the invention does not necessarily describe all necessaryfeatures of the present invention. The present invention may also be asub-combination of the features described above. The above and otherfeatures and advantages of the present invention will become moreapparent from the following description of the embodiments taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of a DUT mounting board according to thepresent invention.

FIG. 2 shows a second embodiment of a DUT mounting board according tothe present invention.

FIG. 3 shows a third embodiment of a DUT mounting board according to thepresent invention.

FIGS. 4A and 4B show an example of the configurations of a deviceinterface unit of an IC testing apparatus.

FIG. 5 shows an example of the DUT mounting board, and an example of thedetailed configuration of a performance board 300.

FIGS. 6A-6C show an example of enlarged views of a section of a socketsubstrate 350.

FIG. 7 shows an example of the result of measuring reflection componentsthat occur in regard to the example shown in FIG. 6 respectively.

FIG. 8 shows another example of an enlarged view near a single-sidedhole for high frequency 382.

FIG. 9 shows an example of a detailed configuration of a probe card 400that is an example of the DUT mounting board.

FIG. 10 depicts a test of an electronic device.

FIG. 11 shows an example of an upper surface of a holding substrate 30.

FIG. 12 shows an example of cross-sectional views of a holding substrate30 and a connection-unit-side connector 64.

FIG. 13 shows another example of the upper surface of a holdingsubstrate 30.

FIG. 14 shows a schematic structure of a conventional IC testingapparatus.

FIG. 15 shows a conventional structure of DUT mounting board.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described based on the preferred embodiments,which do not intend to limit the scope of the present invention, butexemplify the invention. All of the features and the combinationsthereof described in the embodiment are not necessarily essential to theinvention.

FIG. 1 schematically shows an embodiment of a DUT mounting boardaccording to the present invention, and the parts corresponding to thosein FIG. 15 are given the same symbols and the detailed description willbe omitted.

The DUT mounting board 50 having a multilayer printed wiring substratestructure as an example is connected with electrode pads 21 and 22 onits upper and lower surfaces and an internal layer wiring pattern 24,and uses a through hole 23 and a SVH (Surface Buried Via Hole) 51.

At the both ends of each internal layer wiring pattern 24, one of theseis connected with the through hole 23 and the other is connected withthe SVH 51, and the wiring between the electrode pads 21 and 22corresponding to the lower surface is configured by the SVH 51, theinternal layer wiring pattern 24 and the through hole 23.

FIG. 1 shows the internal layer wiring pattern 24 schematically asthree, and the SVH 51 is formed at the electrode pad 21 for connectingthe device under test 40 with two of these, the SVH 51 is formed at theelectrode pad 22 for connecting the connector 15 with the rest. Which ofboth ends of the internal layer wiring pattern 24 and the SVH 51 will beprovided at is properly decided for example in considering the wiringposition of pins of the internal layer wiring pattern 24 or the numberof the electrode pads 21 at the connection side of the device under test40.

According to the DUT mounting board 50 having the configuration above,by adopting the SVH 51 at either of the both ends of the internal layerwiring pattern 24, it is possible to shorten the length of a stub part25, which is a part using the SVH 51, in comparison to the conventionalDUT mounting board 20 described in FIG. 15, and thus it is possible toreduce the capacity of the stub part 25, so the present invention cancorrespond to the speeding-up of signals.

In addition, in order to configure the SVH 51 at the DUT mounting board50 shown in FIG. 1, a via hole is first formed only at one wiringsubstrate, and then two of wiring substrates are bonded together. InFIG. 1, the chain double-dashed lines show the bonding part (bondingsurface) 52.

FIG. 2 shows another embodiment of the DUT mounting board according tothe present invention, wherein for example a resistor needs to bemounted on a part of the internal layer wiring pattern 24, and the SVH51 is provided on the way of the internal layer wiring pattern 24. InFIG. 2, a numeral 53 shows a device such as a resistor. The device 53 ismounted on a pair of electrode pads 54 in which a pair of the SVH 51 areformed.

The DUT mounting board 55 shown in FIG. 2 is used corresponding to therequired specification. In addition, it is possible to manufacture theDUT mounting board 55 in the same manufacturing method as that of theDUT mounting board 50 described above.

FIG. 3 shows a DUT mounting board 56 having a structure in which a thirdwiring substrate is interposed between two wiring substrates, where thevia hole is formed, to configure the SVH 51 and these three wiringsubstrates are bonded, unlike the structures of the DUT mounting boards50 and 55 shown in FIG. 1 and FIG. 2, and by adopting this structure itis possible to further reduce the capacity of the stub part 25 incomparison to the DUT mounting board 50 shown in FIG. 1.

Although each of the DUT mounting boards 50, 55 and 56 described aboveis called a performance board in regard to the device interface unit 3of the IC testing apparatus shown in FIG. 14, the structure of thedevice interface unit 3 is not limited to the structure shown in FIG.14, and other configuration may be used according to the use and purposeof the IC testing apparatus.

FIGS. 4A and 4B show another example of the configuration of the deviceinterface unit 3 with the test head 2, hereinafter the configurationwill be described briefly.

In FIG. 4A, the device interface unit 3 consists of a performance board60, a plurality of cables 12, which is the same as that in FIG. 14, aplurality of DUT mounting boards 57, generally called a socket board andan IC socket 320.

The performance board 60 has a connector (not shown in the drawing) forthe connection with the test head 2 on its lower surface, and it ismounted on the test head 2 by being connected with the test head 2 inthe connector connection. In this embodiment, the position of the boardcalled the performance board is different from FIG. 14.

The lower and upper ends of the cables 12 are connected respectivelywith the performance board 60 and the DUT mounting board 57 by solder,the IC socket 320 is mounted on the DUT mounting board 57. The number ofthe DUT mounting boards 57 is simplified in FIG. 4A, for example, to be16 or 32.

Meanwhile, in FIG. 4B the device interface unit 3 consists of amotherboard (the motherboard unit) 70 by a plurality of cables 12, aplurality of DUT mounting boards 57 called the socket boards like thoseof FIG. 4A and the IC sockets 320, each of which is mounted on the DUTmounting boards 57.

The cables 12 in the present embodiment has connectors (not shown) atboth upper and lower ends, wherein the lower end is connected directlywith the test head 2 and the upper end is connected with the DUTmounting board 57.

As shown in FIG. 1 to FIG. 3, the structure of the DUT mounting boardaccording to the present invention can be also applied to the DUTmounting board 57, generally called the socket board, of the deviceinterface unit 3 shown in FIG. 4A and FIG. 4B in the same way, and thusit can correspond to the high speed signals.

FIG. 5 shows an example of the DUT mounting board, and an example of thedetailed configuration of the performance board 300. FIG. 5 is across-sectional view of the performance board 300. The performance board300 has the same function and configuration as the DUT mounting boards(50, 55, 56, and 57) described in relation to FIG. 1 to FIG. 4, andallows the electronic device 310 (the device under test 40) and thetesting apparatus for testing the electronic device 310 to beelectrically connected with each other.

The performance board 300 has an IC socket 320, a socket substrate 350,a plurality of high frequency connectors 370 and a plurality of lowfrequency connectors 372.

The IC socket 320 holds the electronic device 310, and allows each ofpins of the electronic device 310 and each of pins of the performanceboard 300 to be electrically connected with each other. In addition, thesocket substrate 350 holds the IC socket 320 on an upper surface of thesocket substrate 350, and is electrically connected with the electronicdevice 310 via the IC socket 320. In addition, the socket substrate 350is electrically connected with the testing apparatus 200 (cf. FIG. 10)via the connection unit 100 (cf. FIG. 10).

A plurality of high frequency connectors 370 and a plurality of lowfrequency connectors 372 are provided at a lower surface of the socketsubstrate 350, receive the test signals, which should be supplied to theelectronic device 310, from the testing apparatus 200 via the connectionunit 100, and supply them to the electronic device 310 via the socketsubstrate 350 and the IC socket 320.

Although it has been describe that one of surfaces of the socketsubstrate 350 facing the electronic device 310 is the upper surface anda surface facing the testing apparatus 200 is the lower surface in thepresent embodiment, a surface facing the testing apparatus 200 may bethe upper surface and a surface facing the electronic device 310 may bethe lower surface in another embodiment.

In addition, the low frequency signal connector 372 is provided at aposition farther from the IC socket 320 than the high frequency signalconnector 370, and receives signals, of which the frequency is lowerthan the test signals supplied to the IC socket 320 by the highfrequency signal connector 370, from the testing apparatus 200 via theconnection unit 100.

The socket substrate 350 is provided with a low frequency signal wiring376, a high frequency signal wiring 380 and a GND wiring at a pluralityof layers in a depth direction. The low frequency signal wiring 376 andthe high frequency signal wiring 380 are an example of the internallayer wiring pattern 24 described in regard to FIG. 1 to FIG. 4.

In addition, the socket substrate 350 is provided with the through holefor low frequency 374 across the plurality of layers, the through holefor high frequency 362, the single-sided hole for low frequency 360, thesingle-sided hole for high frequency 382, and the GND through hole 384.

The through hole for low frequency 374, the through hole for highfrequency 362 and the GND through hole 384 are an example of the throughhole 23 described in relation to FIG. 1 to FIG. 4, and the single-sidedhole for low frequency 360 and the single-sided hole for high frequency382 are an example of the SVH 51 described in relation to FIG. 1 to FIG.4.

The through hole for low frequency 374 is electrically connected withthe low frequency signal connector 372, and is provided to penetratefrom the lower surface, at which the low frequency signal connector 372of the socket substrate 350 is provided, to the upper surface at whichthe electronic device 310 of the socket substrate 350 is placed. In thepresent embodiment, the through hole for low frequency 374 is providedcloser to the circumference of the socket substrate 350 than thesingle-sided hole for high frequency 382, the single-sided hole for lowfrequency 360 and the through hole for high frequency 362.

In addition, the single-sided hole for low frequency 360, which is theSVH 51 described above, is electrically connected to the low frequencysignal pin of the electronic device 310, and is formed from the uppersurface of the socket substrate 350 to an intermediate layer positionnot reaching the lower surface of the socket substrate 350. In thepresent embodiment, the single-sided hole for low frequency 360 isprovided closer to the circumference of the socket substrate 350 thanthe through hole for high frequency 362.

And, the low frequency signal wiring 376 is formed at one of pluralityof layers of the socket substrate 350, allows the through hole for lowfrequency 374 and the single-sided hole for low frequency 360 to beelectrically connected, and transfers the test signals of low frequency.In the socket substrate 350, the GND wiring 378 is formed at a pluralityof layers, and the low frequency signal wiring 376 is formed between anyof the GND wirings 378.

By this configuration, the socket substrate 350 can supply the testsignals of low frequency to the electronic device 310. In addition,since the SVH is used as the single-sided hole for low frequency 360 inorder to be electrically connected with the IC socket 320, it ispossible to reduce the area of the stub part, which does not contributeto transferring the test signals, so that it is possible to transfer thetest signals with high accuracy.

The single-sided hole for high frequency 382, which is the SVH 51described above, is electrically connected with the high frequencysignal connector 370, and is extended from the lower surface, at whichthe high frequency signal connector 370 of the socket substrate 350 isprovided, to an intermediate layer position not reaching the lowersurface of the socket substrate 350.

In addition, the through hole for high frequency 362 is electricallyconnected with the high frequency signal pin of the electronic device310, and is formed to penetrate from the upper surface of the socketsubstrate 350 to the lower surface of the socket substrate 350. And, thehigh frequency signal wiring 380 is formed to be closer to the lowersurface of the socket substrate 350 than a layer, at which the lowfrequency signal wiring 376 is formed, of the plurality of layers of thesocket substrate 350, thereby allowing the single-sided hole for highfrequency 382 and the through hole for high frequency 362 to beelectrically connected with each other, and transferring the testsignals of high frequency. The single-sided hole for high frequency 382is not interrupted by the low frequency signal wiring 376 on its upperlayer, and further, the single-sided hole for low frequency 360 is notinterrupted by the high frequency signal wiring 380 on its lower layer,and therefore it is possible to obtain pattern wiring with high density.

By this configuration, it is possible to supply the test signals of highfrequency to the electronic device 310. In addition, since the SVH isused as the single-sided hole for high frequency 382, it is possible toreduce the area of the stub part, which does not contribute totransferring the test signals, which makes it possible to transfer thetest signals with high accuracy. Further, by providing the single-sidedhole for high frequency 382 more inwardly than the through hole for lowfrequency 374, it is possible to shorten the transfer route length ofthe test signals of high frequency and to transfer the test signals withhigh accuracy.

In addition, the GND wiring 378, which is formed at the plurality oflayers and is a ground surface having an entire solid surface formed atalmost all surfaces of the GND layer, is electrically connected with theGND through hole 384, and is connected with the ground voltage via theGND through hole 384. In addition, although FIG. 5 shows only one GNDthrough hole 384, a plurality of GND through holes 384 is provided witha required pitch over all surfaces of the socket substrate. In addition,it is provided near the single-sided hole or the through hole such asthe single-sided hole for high frequency 382.

FIGS. 6A-6C show an example of an enlarged view of a section of thesocket substrate 350. As described above, the socket substrate 350 isprovided with the GND wiring 378 at a plurality of layers in the depthdirection, and the signal wiring of the low frequency signal wiring 376or the high frequency signal wiring 380 is designed to have acharacteristic impedance of for example 50Ω when formed at the layerbetween the GND wirings 378.

Moreover, in the GND layer of the socket substrate 350, in the area atwhich the through hole for low frequency 374, the single-sided hole forhigh frequency 382, the single-sided hole for low frequency 360 and thethrough hole for high frequency 362 are formed, predetermined patternsneed to be formed at each of the GND layers between the through hole orthe single-sided hole and the GND wiring 378. That is, it is required toform the through hole or the single-sided hole and the GND wiring 378 tohave a predetermined interval in a horizontal direction of each of theGND layers. In the present embodiment, the through hole or thesingle-sided hole and the GND wiring 378 are formed to be about 0.3mm-0.35 mm.

FIG. 6A shows an example of an enlarged view near the through hole forlow frequency 374. In the present embodiment, the GND wiring 378 inregard to each of the GND layers is formed in order not to exist in acircular area, which is a circule concentric with the through hole forlow frequency 374 and its diameter is larger than the through hole forlow frequency 374. In the present embodiment, the GND wiring 378 inregard to each of the GND layers is formed in order not to exist in acircular area having the diameter of 0.75 mm, which is a circleconcentric with the through hole for low frequency 374.

FIG. 6B shows another example of an enlarged view near the through holefor low frequency 374. In the present embodiment, the GND wiring 378 inregard to each of the GND layers is formed in order not to exist in acircular area, of which the diameter is larger than the exampledescribed in regard to FIG. 6A. In the present embodiment, the GNDwiring 378 is formed in order not to exist in a circular area having thediameter of 1.25 mm, which is a circle concentric with the through holefor low frequency 374.

By these configurations, the distance between the through hole for lowfrequency 374 and the GND wiring 378 can be broaden, consequently, thecapacitance that occurs between the through hole for low frequency 374and the GND wiring 378 can be reduced, and thus it is possible totransfer the test signals with high accuracy. In addition, it ispreferable to have the same configuration as FIG. 6B in regard to thevicinity of the through hole for high frequency 362.

FIG. 6C shows an example of an enlarged view near the single-sided holefor high frequency 382. As shown in FIG. 6C, the single-sided hole ofthe single-sided hole for high frequency 382 or the single-sided holefor low frequency 360 is formed in order not to penetrate the socketsubstrate 350. Due to this, if the single-sided hole extends to theupper or lower surface of the socket substrate 350, the GND wiring 378is formed at an area where the single-sided hole is formed.

In addition, as described above, since the socket substrate 350 isformed by bonding a plurality of substrates where the single-sided holeis formed as the penetrating hole, each of the lengths of thesingle-sided holes (SVH) in a depth direction are constant. Due to this,if electrically connected with the signal wiring in regard to each ofthe layers having different depths, the stub part that does notcontribute to transferring the test signals occurs even though the SVHis used.

Accordingly, a plurality of GND wirings 378 is divided into the upperlayer GND wiring 378-2, which is formed closer to a layer of the uppersurface of the socket substrate 350 than the high frequency signalwiring 380, and the lower layer GND wiring 378-1, which is formed closerto a layer of the lower surface of the socket substrate 350 than thehigh frequency signal wiring 380.

As shown in FIG. 6C, by allowing the distance in a horizontal directionbetween at least a part of a plurality of upper layer GND wirings 378-2and the single-sided hole for high frequency 382 to be larger than thedistance in a horizontal direction between the lower layer GND wiring378-1 and the single-sided hole for high frequency 382, it is possibleto reduce the capacitance in regard to the stub part. That is, supposingthe diameter of a circular shape is x, in which the lower layer GNDwiring 378-1 is not formed, in regard to an area, where the single-sidedhole for high frequency 382 is formed, of a layer where the lower layerGND wiring 378-1 is designed to be formed, it is preferable that x issmaller than 1.25 mm.

In addition, it is preferable that the distance in a horizontaldirection between one of a plurality of the upper layer GND wirings378-2 nearest to the high frequency signal wiring 380 and thesingle-sided hole for high frequency 382 is approximately the same asthe distance in a horizontal direction between the lower layer GNDwiring 378-1 and the single-sided hole for high frequency 382, and issmaller than the distance in a horizontal direction between the other ofthe upper layer GND wirings 378-2 and the single-sided hole for highfrequency 382. By this configuration, it is possible to reduce theinfluence of the noise in regard to the high frequency signal wiring 380in addition to reducing the capacitance in regard to the stub part.

FIG. 7 shows an example of the result of measuring reflection componentsthat occur in regard to the example shown in FIGS. 6A, 6B and 6C,respectively. In FIG. 7, the horizontal axis represents the reflectioncomponent, and the vertical axis represents the position where thereflection occurs. In addition, (a) in FIG. 7 represents the magnitudeof the reflection component in regard to the example shown in FIG. 6A,(b) represents the magnitude of the reflection component in regard tothe example shown in FIG. 6B and (c) represents the magnitude of thereflection component in regard to the example shown in FIG. 6C.

As shown in FIG. 7, in regard to the example shown in FIG. 6A, thereflection component of −19.5% occurs against the test signals in thestub part of the single-sided hole. Meanwhile, in regard to the exampleshown in FIG. 6B, the reflection component of −12.5% occurs against thetest signals, it is understood that the reflection component is reducedby broadening the distance between the single-sided hole and the GNDwiring 378.

In addition, in regard to the example shown in FIG. 6C, the reflectioncomponent of −7.2% occurs against the test signals, it is understoodthat the reflection component is further reduced by forming the GNDwiring 378 as shown in FIG. 6C by using the single-sided hole (SVH) asan alternative to the through hole.

FIG. 8 shows another example of an enlarged view near the single-sidedhole for high frequency 382. The present embodiment is an examplewherein the GND wiring 378 is removed in regard to the area 390. By thisconfiguration, it is possible to transfer the test signals with furtherhigh accuracy by reducing the capacitance that occurs between the GNDwiring 378 formed over the stub part and the single-sided hole for highfrequency 382.

Moreover, in the present embodiment, in regard to each of the GNDlayers, the diameter of the circular area where the GND wiring 378 isnot formed is set to be 1.5 mm. Although it is desirable that thediameter of the circular area is as large as possible while the GNDlayer adjacent to the high frequency signal wiring 380 is removed, thesize is limited because the GND through hole 384 is formed over allsurfaces of the socket substrate 350 as described above. That is, it ispreferable that the diameter of the circular area, where the GND wiring378 in regard to each of the GND layers is not formed, is formed aslarge as possible in a range in order not to overlap by having apredetermined margin to the GND through hole 384 formed over allsurfaces of the socket substrate 350.

FIG. 9 shows an example of a detailed configuration of a probe card 400that is an example of the DUT mounting board. FIG. 9 is across-sectional view of the probe card 400. In FIG. 5 to FIG. 8,although it is electrically connected with the electronic device 310 byusing the performance board 300, it may be electrically connected withthe electronic device 310 by using the probe card 400 as an alternativeto the performance board 300.

In this case, the probe card 400 has the same function and configurationas those of the performance board 300. In the present embodiment, theprobe card 400 has, in regard to the configuration of the performanceboard 300, a plurality of probe pins 364 electrically connected with theterminals of the electronic device 310 as an alternative to the ICsocket 320. In this case, the socket substrate 350 is functioning as aprobe substrate for holding the probe pins 364. In addition, when usingthe probe card 400, the electronic device 310 can be tested in the formof a wafer without a package.

Next, a connection unit for connecting the performance board 300 or theprobe card 400 and a testing apparatus body will be described. Theconnection unit is an example of the motherboard 70 described in regardto FIG. 4.

FIG. 10 depicts an overall system configuration for testing anelectronic device. As described in FIG. 4, the electronic device 310 tobe tested is placed on the performance board 300 which is an example ofthe DUT mounting board. The performance board 300 has the same functionand configuration as the performance board 300 described in regard toFIG. 5 to FIG. 8. The testing apparatus 200 generates the test signalsfor testing the electronic device 310 such as a semiconductor device. Inaddition, the connection unit 100 connects the testing apparatus 200 andthe performance board 300 electrically, and supplies the test signals tothe electronic device 310 placed on the performance board 300.

The testing apparatus 200 generates the test signals having a desiredpattern corresponding to the electronic device 310, and supplies them tothe electronic device 310 via the connection unit 100 and theperformance board 300. In addition, the testing apparatus 200 receivesthe output signals from the electronic device 310 via the connectionunit 100 and the performance board 300. The testing apparatus 200generates the expected signals corresponding to the electronic device310, compares them with the output signals received and judges thepass/fail of the electronic device 310.

The performance board 300 has a socket substrate 350, an IC socket 320,a plurality of performance-board-side connectors 330 and a plurality ofsignal wirings 340. The performance board 300 holds the plurality ofperformance-board-side connectors 330 on a surface facing the connectionunit 100, and holds the IC socket 320 on an upper surface opposite tothat facing the connection unit 100. The performance-board-sideconnectors 330 are, for example, the high frequency signal connector 370and the low frequency signal connector 372 described in regard to FIG.5.

The IC socket 320 holds the electronic device 310. In addition, the ICsocket 320 has terminals electrically connected with each of the pins ofthe electronic device 310.

The plurality of performance-board-side connectors 330 receives the testsignals, which are supposed to be supplied to the electronic device 310,from the testing apparatus 200 via the connection unit 100, and suppliesthem the IC socket 320 via the signal wiring 340. In addition, itreceives the output signals of the electronic device 310 and suppliesthem to the connection unit 100. Here, the signal wiring 340 correspondsto the high frequency signal wiring 380, the single-sided hole for highfrequency 382, the through hole for high frequency 362, the through holefor low frequency 374, the low frequency signal wiring 376 and thesingle-sided hole for low frequency 360, which have been described inregard to FIG. 5.

In the present embodiment, the performance-board-side connector 330 cprovided near the IC socket 320 receives the test signals of highfrequency among the test signals to be supplied to the electronic device310, and is functioning as the high frequency signal socket 370 forsupplying the test signals to the IC socket 320. In addition, theperformance-board-side connectors (330 a and 330 b), which are providedat positions farther from the IC socket 320 than theperformance-board-side connector 330 c, receive the signals having thelower frequency than the test signals supplied to the IC socket 320 bythe performance-board-side connector 330 c from the testing apparatus200 via the connection unit 100, and are functioning as the lowfrequency signal connector 372 for supplying the test signals to the ICsocket 320.

The positions of these performance-board-side connectors 330 changecorresponding to the number of the IC pins of the electronic device 310and the IC pin arrangement. In addition, the performance-board-sideconnector 330 for receiving signals of higher frequency is provided tobe nearer to the IC socket 320. Therefore, the distance to the IC socket320 is changed by the electronic device 310. Further, theperformance-board-side connectors (330 a and 330 b) provided atpositions far from the IC socket 320 may supply the source voltage ofthe electronic device 310.

According to the performance board 300 in the present embodiment, sincethe performance-board-side connector 330 is provided at a positioncorresponding to the frequency of the received signals, it is possibleto supply the signals to the electronic device 310 with good transfercharacteristic. The performance board 300 is made with a board whereinthe positions of the performance-board-side connectors 330 changecorresponding to the number of the IC pins of the electronic device 310and the IC pin arrangement.

The connection unit 100 has a holding substrate 30, a plurality ofconnection-unit-side connectors 64 and a plurality of connection cables(66 a, 66 b and 66 c). The holding substrate 30, which is a structuralbody for fixing a plurality of connection-unit-side connectors 64 at apredetermined position, is provided on a side facing the performanceboard 300. In addition, the holding substrate 30 holds a plurality ofconnection-unit-side connectors 64 in regard to a surface facing theperformance board 300.

A plurality of connection-unit-side connectors (64 a, 64 b and 64 c) isprovided on the holding substrate 30 to be attachable to and detachablefrom the holding substrate 30 in order to be reused in common, and isconnected with the performance-board-side connectors (330 a, 330 b and330 c) provided in the performance board 300. For example, the pluralityof connection-unit-side connectors 64 can be commonly used by changingthe holding substrate 30 corresponding to a position of theperformance-board-side connector 330 in regard to the performance board300 to be connected.

A first end of each of the connection cables 66 is fixed to thecorresponding connection-unit-side connector 64, and connects theconnection-unit-side connector 64 and the testing apparatus 200electrically. The testing apparatus 200 is connected to a second end ofthe connection cables 66, supplies the test signals to the connectionunit 100 via this connection and receives the output signals outputtedby the electronic device 310 from the connection unit 100 via theconnection cables 66.

According to the connection unit 100 in the present embodiment, by onlychanging the cheap holding substrate 30, it is possible to connect aplurality of kinds of performance boards 300 wherein the arrangement ofthe performance-board-side connector 330 is different. Due to this, itis possible to obtain a great advantage capable of reusing a pluralityof connection-unit-side connectors 64 without changing them.

Moreover, although the test signals are supplied to the electronicdevice 310 by using the performance board 300 in the present embodiment,the test signals may be supplied to the electronic device 310 by usingthe probe card 400 as described in regard to FIG. 9 in anotherembodiment.

FIG. 11 shows an example of an upper surface of the holding substrate30. When the connection unit 100 and the performance board 300 areconnected, the electronic device 310 is placed at a placement position312.

The plurality of connection-unit-side connectors 64 (cf. FIG. 10) isattachable and detachable, and can move to the plurality of arrangementpositions 34. For example, a plurality of arrangement positions 34 isprovided on the holding substrate 30 in order to change the mutualdistance in regard to the holding substrate 30 of a plurality ofconnection-unit-side connectors 64 as shown in FIG. 11. In addition, asshown in FIG. 11, a plurality of arrangement positions 34 is provided onthe holding substrate 30 in order to change the distance of a pluralityof connection-unit-side connectors 64 to the placement position 312 ofthe IC socket 320. In addition, if a probe card is used as analternative to the performance board 300, the placement position 312 ofthe IC socket 320 becomes the mounting position of the probe pin.

In addition, the holding substrate 30 has a positioning member 42 forholding the connection-unit-side connector 64 at each of the arrangementpositions 34. Due to this, the arrangement position 34 is used to changethe connection-unit-side connector 64.

In addition, the holding substrate 30 has a penetrating hole 32, ofwhich the size is fit for passing the connection-unit-side connector 64,at each of the arrangement positions 34. The penetrating hole 32 isprovided across a surface facing the testing apparatus 200 from asurface facing the performance board 300 of the holding substrate 30. Ifthe mounting position of the connection-unit-side connector 64 ischanged, the connection-unit-side connector 64 is taken out through thetesting apparatus 200 via the penetrating hole 32, and is mountedthrough the performance board 300 via the penetrating hole 32corresponding to the arrangement position 34 to which it is supposed tobe moved. Due to this, even though the connection cable 66 (cf. FIG. 10)is fixed to the connection-unit-side connector 64, it is possible tomove the connection-unit-side connector 64 to a desired position.Therefore, there is a great advantage to be able to reuse theconnection-unit-side connectors 64.

In addition, the penetrating holes 32 may be provided across a pluralityof arrangement positions 34. That is, the opening parts of thepenetrating holes 32 may be provided across a plurality of arrangementpositions 34. For example, the opening part of the penetrating hole 32-1and the opening part of the penetrating hole 32-4 shown in FIG. 11 maybe connected to be one penetrating hole. In this case, if theconnection-unit-side connector 64 is moved from the arrangement position34-1 to the arrangement position 34-4, it is possible to change theposition of the connection-unit-side connector 64 easily because theconnection cables 66 can pass through the penetrating hole from thearrangement position 34-1 to the arrangement position 34-4.

And, as shown in FIG. 11, it is preferable that a plurality ofarrangement positions 34 is provided so as to change the position of theconnection-unit-side connector 64 in both radial and circumferentialdirections taking the placement position 312 of the IC socket 320 as acenter.

Moreover, in the present embodiment, the cross-sections of the IC socket320 and the connection-unit-side connector 64 in regard to a surfaceapproximately parallel to the holding substrate 30 are rectangular. Inthe radial direction, if the connection-unit-side connector is held atthe arrangement position 34 nearest to the placement position 312 of theIC socket 320, it is preferable that the holding substrate 30 holds theconnection-unit-side connector 64 in order that the long side of thesection of the connection-unit-side connector 64 faces the nearest sideof the section of the IC socket 320. For example, the positioning member42 provided at the arrangement position 34-4 holds theconnection-unit-side connector 64 in order that the long side of theconnection-unit-side connector 64 is approximately parallel to thenearest side of the section of the IC socket 320. A plurality ofterminals are provided in the connection-unit-side connector 64 alongthe long side direction, thus when the connection-unit-side connector 64is provided near the IC socket 320 to which the signals of highfrequency are supposed to be supplied, it is possible to set thedistance between each of the terminals and the pins of the electronicdevice 310 to be approximately the same, and thus it is possible tosupply the signals to the electronic device 310 with good transfercharacteristics.

In addition, the holding substrate 30 has a small diameter performanceboard positioning member 46 and a large diameter performance boardpositioning member 44. For example, the small diameter performance boardpositioning member 46 and the large diameter performance boardpositioning member 44 may be a plurality of protrusions which areprovided on a surface of the holding substrate 30 facing the performanceboard 300 for fitting with the performance board 300.

The small diameter performance board positioning member 46 sets theposition to hold the performance board 300 of which the diameter is lessthan a predetermined size. In addition, the large diameter performanceboard positioning member 44 is provided at a position, on the holdingsubstrate 30, farther from the placement position 312 of the IC socket320 than the small diameter performance board positioning member 46, andsets the position to hold the performance board 300 of which thediameter is more than a predetermined size. According to the connectionunit 100 in regard to the present embodiment, it is possible to connecta plurality of kinds of performance boards 300 having differentdiameters with high accuracy.

FIG. 12 shows an example of cross-sectional views of the holdingsubstrate 30 and the connection-unit-side connector 64. As describedabove in regard to FIG. 11, the holding substrate 30 has the positioningmember 42 on a surface to hold the connection-unit-side connector 64. Inthe present embodiment, the positioning member 42 is a protrusion whichextends in a direction to the connection-unit-side connector 64.

The connection-unit-side connector 64 has a groove 12 for being engagedwith the positioning member 42 on a surface facing the holding substrate30. By engaging the positioning member 42 and the groove 12 of theconnection-unit-side connector 64, it is possible to hold theconnection-unit-side connector 64 on the holding substrate 30. Inaddition, the positioning member 42 may be a groove in shape, while theconnection-unit-side connector 64 may have a protrusion to engage withthe positioning member 42.

FIG. 13 shows another example of the upper surface of the holdingsubstrate 30. In the present embodiment, two IC sockets 320 are placedon the performance board 300. The connection unit 100 has a plurality ofconnection-unit-side connectors 64 provided corresponding to theplurality of IC sockets 320.

The holding substrate 30 holds the corresponding connection-unit-sideconnector 64 in order to change the position on the holding substrate 30corresponding to the placement positions 312 of each of the IC sockets320. That is, the holding substrate 30 has the function andconfiguration described in regard to FIG. 11 for each of the IC sockets320. For example, by passing the connection-unit-side connector 64through a penetrating hole not shown, it is possible to move theconnection-unit-side connector 64 to a desired position.

Although the present invention has been described by way of exemplaryembodiments, it should be understood that those skilled in the art mightmake many changes and substitutions without departing from the spiritand the scope of the present invention which is defined only by theappended claims.

As obvious from the description above, according to the DUT mountingboard in relation to the present invention, it is possible to decreasethe stub capacitance of the through hole part, and thus it is possibleto obtain the DUT mounting board suitable for high speed signals.

In addition, since the device interface unit of the testing apparatushas such DUT mounting board, it is possible to obtain good waveformquality in regard to high speed signals, and to perform the test withhigh speed.

In addition, according to the connection unit in relation to the presentinvention, it is possible to supply the signals to the electronic devicewith good transfer characteristic by connecting a plurality of kinds ofperformance boards or probe cards. Due to this, it is possible to testthe electronic device with high accuracy.

1. A probe card for electrically connecting an electronic device with atesting apparatus for testing said electronic device, said probe cardcomprising: a probe pin for being electrically connected to a terminalof said electronic device, a probe board for holding said probe pin, ahigh-frequency signal connector for supplying a test signal from saidtesting apparatus to said probe pin, and a low-frequency signalconnector, provided farther from said probe pin than a position of saidhigh-frequency signal connector, for supplying a test signal, of which afrequency is lower than said test signal supplied to said probe pin bysaid high-frequency signal connector.